Noob ceiling Q's: beams, ducts, and tiles (oh my!)

Post and discuss acoustic topics, Studio design, construction, and soundproofing here

Noob ceiling Q's: beams, ducts, and tiles (oh my!)

Postby Rob Darst » Sat Jan 14, 2006 8:14 pm

Hi all,

Please indulge a few newbie questions--I am sure you have answered them before, but my searches didn't turn up answers--at least none that I could understand.

I want to build a basement room with an isolated ceiling (ideally, two layers of drywall suspended from RSIC-1 clips). A supporting beam transverses the entire room-to-be below the joists, and in several places HVAC ducts and plumping pipes do so as well. In other words, a cross-section of the suspended ceiling might look like this:

       _______________                           ________________
pipe |                            | beam        duct  |                               | duct
____|                            |_____________|                               |_____

(1) From the little I know about room acoustics, it seems to me that the "boxing out" of these items should be part of the suspended ceiling itself, and not connected to them or the joists in any other way. In other words, the whole ceiling, boxes and all, would be one suspended unit. Is that correct?

(2) For ventilation, my plan is to tap the first floor HVAC system, since both the outgoing and return conduits run through this space. I am guessing that the best way to connect the main conduits to the vents in the suspended ceiling would be to install 180-degree loops of lined flexible ducting between the joists. Will that work?

(3) There are a couple of water meters above the ceiling-to-be that I will need to read occasionally, so I will need to install access panels beneath these. Any tips on how to do this while minimizing increased noise transmission through the ceiling?

(4) Finally, my wife would like to hang an Armstrong tiled ceiling below the drywall, into which we could place recessed lighting cans. Would this create a "three leaf" problem? The "default" tiles (Sahara) have a CAC of 35. I don't know how CAC values relate to STC values, so I don't know how much of a "mass" this is.

Thank you!
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Bob » Sat Jan 14, 2006 9:11 pm

Rob:

Where are you in the world? Addvice changes from place to place. (Please update your user profile).
Please read this
http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3231
And answer those questions, including what you are doing in this room, and pictures.

I liked your diagram here better
http://www.avsforum.com/avs-vb/showthread.php?t=631089

Hmm. Threads on various topics in various forums. Here's one on ventilation.
http://www.avsforum.com/avs-vb/showthread.php?t=630417
(You know it's easier for everyone to figure out things about your situation if they're all in one thread.)

(1) From the little I know about room acoustics, it seems to me that the "boxing out" of these items should be part of the suspended ceiling itself, and not connected to them or the joists in any other way. In other words, the whole ceiling, boxes and all, would be one suspended unit. Is that correct?

By 'Room Acoustics' I usually mean in the room (mineral fiber).
By 'Boxing out' I usually think of soundproofing (drywall).
I assume you're talking about soundproofing, and yes decoupling is a good thing, and if you're using RSIC then there's little point in shorting it out (flank around the RSIC) by connecting the ceiling drywall rigidly to the joists at the ducts.
a) ceiling drywall screwed to joists - coupled, not as good.
b) ceiling drywall hung from RSIC - a little decoupled, better
c) ceiling drywall hung from new room-in-a-room joists - maximially decoupled, best

Did you have something like this in mind (not a recommendation, a question)?
http://www.bobgolds.com/ceiling/SlopedF ... Soffit.gif

(2) For ventilation, my plan is to tap the first floor HVAC system, since both the outgoing and return conduits run through this space. I am guessing that the best way to connect the main conduits to the vents in the suspended ceiling would be to install 180-degree loops of lined flexible ducting between the joists. Will that work?
As long as you don't stall the air. HVAC professionals do not use long runs (e.g. longer than 10') of flexible ducting (actually what you want is flexable acoustic ducting, not just flexible). Consider something like Johns Mansville SuperDuct instead. Yes a couple of bends are good. The minimum angle is one that you can't see through (so the sound has to impact with the absorbing walls of the duct). You want lots of slow moving air.

(3) There are a couple of water meters above the ceiling-to-be that I will need to read occasionally, so I will need to install access panels beneath these. Any tips on how to do this while minimizing increased noise transmission through the ceiling?
Some sort of door. Have a look at the BBC Door Blanks PDF. Use General Motor's Rubber Trunk Gaskets to make it air tight. A piano hinge. And Brass Fitch or two to hold it shut.

(4) Finally, my wife would like to hang an Armstrong tiled ceiling below the drywall, into which we could place recessed lighting cans. Would this create a "three leaf" problem? The "default" tiles (Sahara) have a CAC of 35. I don't know how CAC values relate to STC values, so I don't know how much of a "mass" this is.
Please give us a URL link to this product.

NRC vs CAC:
http://www.armstrong.com/commceilingsna ... 22533.html
Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Rob Darst » Sat Jan 14, 2006 10:13 pm

Hi Bob,

Many thanks for the quick response.

I live in southeastern Connecticut, just over the river from Rhode Island, in the USA.

I apologize for posting the same question on more than one forum. I figured that would maximize the odds of getting a good range of advice. I honestly didn't realize that this was a breach of ettiquette.  :oops:

I've broken up my questions because (1) I didn't want to make my posts overwhelmingly long, and (2) as I have been learning about soundproofing over the last week, answers have led to new questions. A week ago I knew NOTHING about ANY of this! To make things even worse, I knew equally little about home construction more generally. As you can tell from my posts, my level of knowledge still remains embarrassingly low.

The room will change in its purpose over time, but right now the main application driving the specs (and the whole undertaking) is to create a space within which my son can practice his drums without giving everyone else in the house a headache. With the drumheads undampened, the noise level at the top of the basement stairs is 100 dB (I kid you not).

Our situation is kind of strange (and time-urgent) because we signed a contract with Owens Corning a couple of weeks ago to build the room, and then only afterwards discovered that they know next to nothing about soundproofing. The salesman didn't know the difference between absorption and isolation, and at the time, neither did I. When I began talking to the installer, I realized the difference. That's the point at which I began desperately educating myself. We are now trying to reengineer the room plan within the price agreed in the original contract. The project manager is coming over on Monday, by which time I need to have at least a little knowledge about what needs to be done--and I'm well aware that a little knowledge is a dangerous thing.

On to the questions I asked THIS time:

(1) Your diagram of the ceiling is EXACTLY what I had in mind. Is that sort of "three dimensional" suspended ceiling particularly difficult or expensive? (I know the OC guy will claim that it is.)

(2) And now my ignorance will REALLY REALLY show: What are room-within-a-room joists, and what would be the added costs and benefits of going this route?

(3) Do you know of any decent prefabricated access panels? I might be able to work a couple of those into the new room plan.

Thanks again for your indulgence, and again my apologies for my "bad form." I'm learning ettiquette as I go, too!

Rob
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Rob Darst » Sat Jan 14, 2006 10:29 pm

Oops, I forgot the link to the Armstrong Sahara panels: http://www.armstrong.com/resclgam/na/ceilings/en/us/prod_detail.asp?itemId=44727.0

There's not that much information there. The Sahara is the Owens Corning standard. I got the NRC and CAC ratings from Armstrong by telephone.

Would it be correct to say that, in order to minimize the three-leaf problem, the CAC should be as low as possible?
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Bob » Sat Jan 14, 2006 11:57 pm

Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Bob » Sun Jan 15, 2006 12:06 am

I apologize for posting the same question on more than one forum.

I believe that posting on more than one forum is fine, provided you give the first forum 48 hours to respond before posting to the second.

I've broken up my questions because (1) I didn't want to make my posts overwhelmingly long

You've got one subject, and you're in a hurry -- how to treat your basement to deal with drums etc.
Sorry if I seem to be coming on strong on this topic -- it's not that important. :)

If trying to soundproof, I wouldn't start with Sahara (because it's too thin and has air gaps), nor the Owens Corning Basement Finishing System (as I recall it's absorbtion like office particians and not drywall or anything else that would keep the sound in the room).
Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Rob Darst » Sun Jan 15, 2006 1:00 am

Hey Bob,

You're a saint. Let me make sure I understand the joist issue: the "room-within-a-room" joists attach to the tops of the walls of the RWAR, rather than the existing joists/floor above?

With regard to the ceiling tiles, my concern was that they might be TOO "massy." If suspended below the suspended drywall ceiling, I feared this might generate a mass - air - mass - air - mass system, which (as I understand things at this point) might be worse than no suspended tile ceiling at all. (The advantage of the suspended tile ceiling is that we would put recessed lighting in it without cutting into the "real" ceiling, and it would look nicer.) But it sounds as though you think heavier tiles would be better, if we are using a drop-down subceiling?

You're absolutely right about the OC basement system--as I have learned since signing the contract, their system is designed to keep the room quiet, not to decrease transmission of sound from one room to another. Most people who use OC are interested in putting regular rec rooms, bedrooms, etc. in the basement. The nice things about the OC system (and it really is quite nice, for what it is) are (1) it dampens sound WITHIN the room (the drummer could keep his hearing) and (2) you don't have to worry too much about moisture buildup along the exterior walls, because (a) the wall material is porous to water vapor, and (b) you can yank the panels off very easily in the event of a problem or suspected problem. What went wrong is that the sales representative didn't understand the limitations of his product: we had our son play his drums right away to demonstrate our main problem, and the salesman assured us that the OC system would reduce noise levels by 95% (their official number) OUTSIDE as well as inside the room. You of course instantly realize that this is impossible, as I did after I started doing research after a conversation with the head installer a week or so later.

Why not just abandon Owens Corning, you ask? Remember, we live in America, the land of the litigant and the home of the plaintiff, so the fact that we have signed a contract (and paid a hefty deposit) are very meaningful facts. The upside is that the regional OC franchise really wants this job, because we live in a large new development filled with large unfinished basements. We would be the second job in the development, doubling the word-of-mouth advertising base. Once I figured out that the OC product would not perform as promised, I called to complain, and the project manager basically said, "Let's see if we can meet your concerns within the existing contract, even if OC has to pay more." So I'm frantically trying to figure out what to reasonably demand. At best, we will get both isolation and absorption in the new room, and quickly too. At worst, the OC manager will agree to dissolve the contract and give us our deposit back.

Now, I say this assuming that flanking noise through the concrete walls (three sides of the space, which looks very much like the one in your "before" pictures) will be a relatively minor problem. The concrete walls are all underground, so (as I dimly understand these things) the sound waves passing through the OC fiberglass "walls" will largely dissipate into the ground outside, leaving the ceiling and the new interior wall as the weak links in the noise-reduction chain. Is that correct, in your opinion? We aren't looking for library-grade silence here; when Adam plays (which he just started doing), the whole house shakes!

Thanks,
Rob
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Bob » Sun Jan 15, 2006 9:26 am

(1) it dampens sound WITHIN the room (the drummer could keep his hearing)

Sometimes what happens is he just plays louder until it's the volume he likes.
Always what happens with a stereo is people turn the stereo up until it's the volume they like, or until the speakers distort.
The only time it absorbtion lowers the volume in the room is if people aren't involved in the volume -- such as the noise by a furnace or other machine.

the OC system would reduce noise levels by 95%
95% energy, is 1/20th the energy, is 13dB.
So assuming that's realistic, if it was 100dBA before, it would be 77dBA after. I'm pretty sure you'll still hear that, as 77dBA is louder than I listen to my home theatre.

Let me make sure I understand the joist issue: the "room-within-a-room" joists attach to the tops of the walls of the RWAR, rather than the existing joists/floor above?
Yep.

But it sounds as though you think heavier tiles would be better, if we are using a drop-down subceiling?
I thought you meant the tiles instead of a ceiling in your basement. If you want to put up a false ceiling under a real MSM ceiling, why not use a regular absorber ceiling?

I say this assuming that flanking noise through the concrete walls
That I don't really know so well.
I know what the usual rules are.
a) do the ceiling and the walls. Leave an inch airspace between the 2x4's holding up the walls and the concrete foundation walls.
b) do the HVAC
c) do the doors
d) if it's a basement concrete floor over earth, it's a damping system -- as sound hits it in the middle and travels to the edges it gets quieter. How much quieter I don't know, perhaps just a bit.
e) for drums on concrete basement floors, there was a story about a fellow who's house was on bedrock, and his neighbour didn't hear the drums because their house was on soft earth, but the next house beond that was on the same bedrock and they complained about the drums.
f) drums are low frequency noise (hard to stop), and impact. So put them up on a decoupled riser.

Dennis Erskine is fond of likening soundproofing to an aquarium. If there's a hole in the side, the water leaks out. If there's a hole in the walls or ceiling or floor, the sound leaks out. Sound will tarvel through the weakest link, whatever that is.

The other thing about OC is that it's about 2" of insulation everywhere. That means that all the HF will be sucked out of the room, but not the LF. Might make for a wierd room acoustically. Certainly a sloped RT60.

BTW, what's the edge of the ceiling -- how do you soundproof that part without walls? Certainly the OC stuff doesn't do that.
Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Rob Darst » Sun Jan 15, 2006 6:13 pm

95% energy, is 1/20th the energy, is 13dB. So assuming that's realistic, if it was 100dBA before, it would be 77dBA after. I'm pretty sure you'll still hear that, as 77dBA is louder than I listen to my home theatre.


Believe it or not, I did the same calculation this morning (and even more unbelievably, came up with the "right answer"). I was stunned that "95%" means so little, relative to what an ordinary person would intuitively expect. I imagine that this issue will come up tomorrow when the OC project manager visits.

If you want to put up a false ceiling under a real MSM ceiling, why not use a regular absorber ceiling?


What is that? A different kind of tile/panel, or some other system altogether? (Sorry to be so clueless.)

The other thing about OC is that it's about 2" of insulation everywhere. That means that all the HF will be sucked out of the room, but not the LF. Might make for a wierd room acoustically.


That's a VERY important point--one that I had also better raise tomorrow. Do you know of any readily available online data that would demonstrate this problem, that I could use to help make my case?

BTW, what's the edge of the ceiling -- how do you soundproof that part without walls? Certainly the OC stuff doesn't do that.


One the one side, the edge of the ceiling would be the new interior wall. On the other three sides, I imagined the ceiling extending all the way to the concrete walls (or rather, to within 1/4" of them) and then caulked with acoustical sealant. I imagined that horizontal 2x4s could be bolted to the concrete walls just beneath the ceiling, both to make caulking easier and to make the wall/ceiling intersection like this |_ instead of like this |. The OC wall panels would then be installed within the resulting space.

What a mess! But at least I'm learning an awful lot.

Thanks, Rob
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Bob » Sun Jan 15, 2006 10:42 pm

Rob Darst
If you want to put up a false ceiling under a real MSM ceiling, why not use a regular absorber ceiling? What is that? A different kind of tile/panel, or some other system altogether? (Sorry to be so clueless.)

MSM: is Mass-Spring-Mass. You wrote about triple-leaf and mass-space-mass-space-mass somewhere. The space between leafs is the air spring.
Regular absorber ceiling: I meant those 1/2" ceiling tiles that you find in offices. The white ones with all the little holes that weigh very little. When you take them down they are grey on the other side and are easy to break (by holding them by a corner in one hand). This sort of thing http://www.armstrong.com/commceilingsna ... ilings.jsp
Even better would be to put 9" of fluffy fiberglass pink R31 on top of it.


Do you know of any readily available online data that would demonstrate this problem, that I could use to help make my case?
http://www.owenscorning.com/comminsul/documents/Fiberglas700Series.pdf
page 2 says
2" of 703 (rigid fiberglass, probably similar to what's in the OC basement system)
- at 125hz has an absorbtion coefficient of 0.17
- at 250hz has an absorbtion coefficient of 0.86
- at 500hz has an absorbtion coefficient of 1.14
- at 1000hz has an absorbtion coefficient of 1.07
- at 2000hz has an absorbtion coefficient of 1.02
- at 4000hz has an absorbtion coefficient of 0.98
You can see how it's much less at the lower frequencies, but fairly even from 500hz up.
I'm not sure what the fundimental frequencies are for drums, but I'll bet they're lower than 250hz.

The concrete walls and floor won't contribute much to LF absorbtion.

One the one side, the edge of the ceiling would be the new interior wall.
Good.

On the other three sides, I imagined the ceiling extending all the way to the concrete walls (or rather, to within 1/4" of them) and then caulked with acoustical sealant.
I'm a little woried about that. In your basement with various ducts and things wouldn't that be complex? And then there's flanking.

What I'm about to write I'm a out of my depth on. Certainly any numbers I'll use (like dB/ft) are completely made up.

Flanking sound is a sound path around another thing. "Sound that reaches the receiving room by paths other than through the test specimen. Flanking transmission paths may be airborne or structure-borne." (from: http://zone.ni.com/devzone/nidzgloss.ns ... C6005D6E65 ) Flanking sound through the floor under a wall. Flanking sound through the wall around a ceiling. Construction is of little use if sound energy can reach other rooms by taking sound paths with a lesser resistance.

http://www.alfwarnock.info/sound/Flanking01.html

For one of these numbers that I'm just going to make up, that probably has no bearing on reality, let's say that 4" concrete with dirt on one side can damp sound at a rate of 10dB per foot at some frequency (e.g. 100hz).

Image

http://www.bobgolds.com/Flanking3.gif
Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Rob Darst » Sun Jan 15, 2006 11:12 pm

Thanks again, Bob! Is there a level beyond saint? If so, you've reached it. :)

You're right about the fundamental frequencies of the drums. The kit has a wide range--think how you listen to cymbals to judge treble response when auditioning speakers--but most of the acoustic energy comes from the drums, and especially the bass drum, which produces most of its energy in the 30-80 Hz range. So a system that sucks up the highs while leaving the lows will make drum practice very boomy indeed. I doubt he would notice now, but if he sticks with it he certainly will.

Your presentation of the potential flanking danger is very sobering. It may be the final straw. I will need to be able to present the problem with some data at my disposal, if possible. Do you know of a source of info for things like the damping rate of concrete foundation walls? The floor problem could be addressed with a simple riser for the kit (my plan in any case), but the wall problem may be a showstopper.

Best,
Rob
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Bob » Sun Jan 15, 2006 11:49 pm

Rob Darst

Do you know of a source of info for things like the damping rate of concrete foundation walls?
No.

Brian Ravnaas over at AVS knows a lot about Flanking, because he tries tests of really-good-walls and his results get turned into insignificance due to the flanking limits of the testing facilities. His tests of not-so-good-walls he gets good numbers on because they are so much worse than the flanking limits of the testing facilities.
He might be able to:
a) tell you if you need to worry about flanking in your situation (e.g. with thin wood floors upstairs, and a single layer of gypsum/drywall downstairs on the ceiling -- flanking certainly wouldn't be your largest problem. e.g. with thin wood floors upstairs, and a double layer of drywall hung on RSIC, flanking may or may not be a problem. e.g. with thick wood floors upstairs with a 1.5" layer of concrete and acoutikmat, room-in-a-room joists downstairs, with three layers of drywall with green glue between each -- flanking would be your biggest concern after HVAC.)
b) Do a nice graph to explain flanking relative to a couple of theoretical wall/ceiling systems
c) probably wouldn't use "Perfect Fictional Walls" in his examples.

Keep in mind that most people post here and there for fun. No one deserves an answer, or even a reply. If you get one that's cool. :)


But if you've got a couple of hours to kill while you're waiting, search on this forum for
keywords: concrete
Author: Eric*
Display results as: Posts
That should give you about 45 threads, several with nice pictures.

And if you are an insomniac, please try
http://forum.studiotips.com/viewtopic.php?t=1467
for everything you ever wanted to know about transmission loss, but were afraid to ask. I positively guarantee that if you read all those, you'll know more than me.
(The two 'Available Now' papers on flanking are over 400 pages - about 60% of the way down on that page)
Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Rob Darst » Mon Jan 16, 2006 12:05 am

Good heavens! I never thought for a moment that I deserved an answer from anybody. On the contrary, I have been amazed by the extent to which people like you have been willing to help out of the sheer goodness of your hearts--for which, again, many thanks. Rob
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Scott R. Foster » Mon Jan 16, 2006 12:49 am

Bob rocks.
SRF
Scott R. Foster
 
Posts: 3854
Joined: Mon Feb 02, 2004 12:41 pm
Location: Jacksonville, FL USA

Postby Rob Darst » Mon Jan 16, 2006 1:00 am

Amen, brother, amen.
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Postby Bob » Mon Jan 16, 2006 5:42 am

Rob Darst:

Do you think you can get them to commit to a certain Field Transmission Loss rating spread (from downstairs to upstairs):
e.g.
15dB at 20hz
20dB at 30hz
23dB at 40hz
26dB at 50hz
32dB at 63hz
38dB at 80hz
40dB at 100hz
47dB at 125hz
56dB at 250hz
60dB at 500hz
66dB at 1000hz
68dB at 2000hz
74dB at 4000hz
Make it a condition of a contract amendment that if they don't make it, you don't have to pay them.
Then you can just let them figure it out, or refund and walk away.

BTW, above numbers stolen from http://www.pac-intl.com/pdf_test/test_RAL_TL01-212.pdf.
You might might might be able to attain something as high as above, but certainly less than
http://www.quietsolution.com/04_NRC_-_2 ... _STC74.pdf due both to construction techniques by people who don't know what's soundproofing safe, home flanking limits, and HVAC.

http://www.bobgolds.com/StcVsFstc.htm


BTW, that 95% energy absorbed -- at what frequency ?  I'll bet it's not 95% at 30hz. I'll bet it's 95% at 1000hz, or maybe 95% with an C weighting. I'll bet it's a lot less at 30hz.
Bob
 
Posts: 4359
Joined: Sun Feb 08, 2004 4:37 am
Location: Oakville, Ontario, Canada

Postby Rob Darst » Tue Jan 17, 2006 2:59 am

Hi Bob,

The project manager and the head local installer came by today and it went rather well. The manager is a pretty reasonable guy who knows the limit of his product, but also realizes there he needs to figure out how to deal with basement -> house NR due to the explosion of HT. Since our drumming problem is roughly the same (lots of LF not absorbed by the OC wall panels), he's interested in trying to make it work. He also is rather more knowledgeable about acoustics in general than the other representatives we had encountered earlier. I'll have to watch the installers like a hawk, I know, but at least the boss will understand my complaints!

In the end, we decided to "split the difference" in the basement--not financially, but technologically. The new interior wall, new interior door, and ceiling will be built along RWAR principles. He's checking the cost-effectiveness of all of the specifics, but we agreed firmly on a fully decoupled sound-clip-suspended drywall ceiling and a staggered stud wall. The concrete walls will be left as is, with the OC panels placed directly against them. We've had water and mold trouble in the basement in the past, so we decided that being able to easily yank off the panels in the event of a problem was worth some flanking. The suspended tile ceiling is gone, and the recessed cans along with it; they will hang simple fluorescent tubes instead.

OC doesn't do the floor in any case, so that wasn't an issue; my plan is to build a floating drum kit platform in the short run, and then put in a full floating floor later if need be (e.g., if a rock band coalesces and this becomes their "garage"). We also agreed to handle the ventilation, which shouldn't be a big deal--there is plenty of room for curved flexiduct up between the joists. And, no small benefit, they are ready to start as soon as we iron out the remaining details and get the ventilation ready to go.

We probably won't reach the specs you suggested, though we might well come close. It would certainly be interesting to take before-and-after measurements to compare. Unfortunately, though, all I have at the moment is a Rat Shack SPL meter.

Again, many, many thanks for your help. It really made a world of difference in our being able to work this out. And if we get flanking noise through the concrete walls, we can't complain that we were blindsided!

Cheers,
Rob
Rob Darst
 
Posts: 9
Joined: Wed Jan 11, 2006 6:51 pm
Location: Connecticut, USA

Re: Noob ceiling Q's: beams, ducts, and tiles (oh my!)

Postby jackycypress » Wed Apr 04, 2018 3:28 am

You can isolated your basement by this: suspended acoustical ceiling It is a high quality, fabric covered sound absorbing board designed to reduce unwanted room reflection, flapping and fluttering echoes and providing a more pleasant and accurate listening environment.
jackycypress
 
Posts: 6
Joined: Wed Mar 28, 2018 1:53 pm


Return to Discussion

Who is online

Users browsing this forum: No registered users and 3 guests

cron